National security policymakers are continuously challenged to ensure that the judgments and assumptions underlying policy, force posture, and provision are congruent with the international environment and the role the United States is playing within it. This has become problematic in the 21st century security environment characterized by complexity, connectivity, and rapid change. This analysis offers key insights into what is a shifting security environment and considers how the United States can best respond to it. Dr. Phil Williams argues that we have passed the zenith of the Westphalian state, which is now in long-term decline, and are already in what several observers have termed the New Middle Ages, characterized by disorder but not chaos. Dr. Williams suggests that both the relative and absolute decline in state power will not only continue but will accelerate, taking us into a New Dark Age where the forces of chaos could prove overwhelming.